Open Access Research

Endosperm-specific expression of human acid beta-glucosidase in a waxy rice

Tamara Patti1, Bruno Bembi12, Piero Cristin1, Flavia Mazzarol1, Erika Secco1, Carla Pappalardo3, Rita Musetti3, Maurizio Martinuzzi3, Serena Versolatto3, Roberta Cariati2, Andrea Dardis2 and Stefano Marchetti13*

Author Affiliations

1 Transactiva Srl, Via J. Linussio 51, 33100 Udine, Italy

2 Regional Coordination Centre for Rare Diseases, University Hospital S. Maria Misericordia, P.zale S. Maria della Misericordia 15, 33100 Udine, Italy

3 Department of Agriculture and Environmental Sciences, University of Udine, Via delle Scienze 206, 33100, Udine, Italy

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Rice 2012, 5:34  doi:10.1186/1939-8433-5-34

Published: 6 December 2012

Abstract

Background

The deficiency of human acid beta-glucosidase (hGCase) causes Gaucher disease, a rare genetically-inherited disorder currently treated by enzyme replacement therapy using recombinant CHO-derived GCase. In an attempt to provide an alternative and more efficient production system, a chimeric cDNA coding for hGCase operatively linked to the signal peptide of rice glutelin 4 (GluB4) was put under the control of the GluB4 endosperm-specific promoter and inserted into the genome of a waxy rice.

Results

Molecular, immunological and biochemical analyses showed that recombinant hGCase, targeted to the protein storage vacuoles of rice endosperm cells, is equivalent to the native protein and has a glycosylation pattern compatible with direct therapeutic use. Compared to a previous study carried out on transgenic tobacco seeds, enzyme contents per unit of biomass were drastically increased; in addition, differently from what observed in tobacco, rice seed viability was unaffected by hGCase even at the highest production level. Transgenic seed polishing combined with a pretreatment of seed flour greatly facilitated hGCase extraction and purification with an industrially-scalable procedure.

Conclusions

This study opens up the possibility to efficiently produce in the rice seed pharmaceutical compounds which are available in limited amounts or completely excluded from clinical practice due to the inadequacy of their production systems.

Keywords:
Human acid beta-glucosidase; Gaucher disease; Transgenic rice; Pharmaceutical proteins; Endosperm-specific expression; Molecular farming